(Lat. intendere, to stretch toward, to aim at) is an act of the will by which that faculty efficaciously desires to reach an end by employing the means. It is apparent from this notion that there is a sharply defined difference between intention and volition or even velleity. In the first instance there is a concentration of the will to the point of resolve which is wholly lacking in the others. With the purpose of determining the value of an action, it is customary to distinguish various sorts of intentions which could have prompted it.

First, there is the actual intention, operating, namely, with the advertence of the intellect. Secondly, there is the virtual intention. Its force is borrowed entirely from a prior volition which is accounted as continuing in some result produced by it. In other words, the virtual intention is not a present act of the will. but rather a power (virtus) come about as an effect of a former act, and now at work for the attainment of the end. The thing therefore that is wanting in a virtual, as contrasted with an actual, intention is not of course the element of will, but rather the attention of the intellect, and that particularly of the reflex kind. So, for example, a person having made up his mind to undertake a journey may during its progress be entirely preoccupied with other thoughts. He will nevertheless be said to have all the while the virtual intention of reaching his destination. Thirdly, an habitual intention is one that once actually existed, but of the present continuance of which there is no positive trace; the most that can be said of it is that it has never been retracted. And fourthly an interpretative intention is one that as a matter of fact has never been really elicited; there has been and is no actual movement of the will; it is simply the purpose which it is assumed a man would have had in a given contingency, had he given thought to the matter.

It is a commonplace among moralists that the intention is the chief among the determinants of the concrete morality of a human act. Hence when one's motive is grievously bad, or even only slightly so, if it be the exclusive reason for doing something, then an act which is otherwise good is vitiated and reputed to be evil. An end which is only venially bad, and which at the same time does not contain the complete cause for acting, leaves the operation which in other respects was unassailable to be qualified as partly good and partly bad. A good intention can never hallow an action the content of which is wrong. Thus it never can be lawful to steal, even though one's intention be to aid the poor with the proceeds of the theft. The end does not justify the means. It may be noted here in passing, as somewhat cognate to the matter under discussion, that the explicit and frequently renewed reference of one's actions to Almighty God is not now commonly thought to be necessary in order that they may be said to be morally good. The old-time controversy on this point has practically died out.

Besides affecting the goodness or badness of acts, intention may have much to do with their validity. Is it required, for instance, for the fulfilment of the law? The received doctrine is that, provided the subject is seriously minded to do what is prescribed, he need not have the intention of satisfying his obligation; and much less is it required that he should be inspired by the same motives as urged the legislator to enact the law. Theologians quote in this connection the saying, "Finis præcepti non cadit sub præcepto" (the end of the law does not fall under its binding force). What has been said applies with even more truth to the class of obligations called real, enjoining for instance the payment of debts. For the discharge of these no intention at all is demanded, not even a conscious act. It is enough that the creditor gets his own.

The Church teaches very unequivocally that for the valid conferring of the sacraments, the minister must have the intention of doing at least what the Church does. This is laid down with great emphasis by the Council of Trent (sess. VII). The opinion once defended by such theologians as Catharinus and Salmeron that there need only be the intention to perform deliberately the external rite proper to each sacrament, and that, as long as this was true, the interior dissent of the minister from the mind of the Church would not invalidate the sacrament, no longer finds adherents. The common doctrine now is that a real internal intention to act as a minister of Christ, or to do what Christ instituted the sacraments to effect, in other words, to truly baptize, absolve, etc., is required. This intention need not necessarily be of the sort called actual. That would often be practically impossible. It is enough that it be virtual. Neither habitual nor interpretative intention in the minister will suffice for the validity of the sacrament. The truth is that here and now, when the sacrament is being conferred, neither of these intentions exists, and they can therefore exercise no determining influence upon what is done. To administer the sacraments with a conditional intention, which makes their effect contingent upon a future event, is to confer them invalidly. This holds good for all the sacraments except matrimony, which, being a contract, is susceptible of such a limitation.

As to the recipients of the sacraments, it is certain that no intention is required in children who have not yet reached the age of reason, or in imbeciles, for the validity of those sacraments which they are capable of receiving. In the case of adults, on the other hand, some intention is indispensable if the sacrament is not to be invalid. The reason is that our justification is not brought about without our co-operation, and that includes the rational will to profit by the means of sanctification. How much of an intention is enough is not always quite clear. In general, more in the way of intention will be demanded in proportion as the acts of the receiver seem to enter into the making of the sacrament. So for penance and matrimony under ordinary conditions a virtual intention would appear to be required; for the other sacraments an habitual intention is sufficient. For an unconscious person in danger of death the habitual intention may be implicit and still suffice for the validity of the sacraments that are then necessary or highly useful; that is, it may be contained in the more general purpose which a man has at some time during his life, and which he has never retracted, of availing himself of these means of salvation at so supreme a moment. For the gaining of indulgences the most that can probably be exacted is an habitual intention.